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NIST SP 800-53 Learning Center

SI-21 — Information Refresh

Read the official control and assessment content, then use the separately labeled Bare Metal Cyber perspective to connect the requirement to implementation, evidence, and sustained operation.

0Enhancements
2Parameters
0Baseline memberships
3Assessment methods

SI — System and Information Integrity · NIST SP 800-53 Release 5.2.0

Official NIST control content

Control statement

Refresh [Organization-defined: information] at [Organization-defined: frequencies] or generate the information on demand and delete the information when no longer needed.

Official NIST discussion

Discussion

Retaining information for longer than it is needed makes it an increasingly valuable and enticing target for adversaries. Keeping information available for the minimum period of time needed to support organizational missions or business functions reduces the opportunity for adversaries to compromise, capture, and exfiltrate that information.

Official OSCAL parameters

Organization-defined parameters

These values must be resolved through the organization’s tailoring and governance process. Bracketed parameter references in the control text identify where a decision is required.

informationthe information to be refreshed is defined;
frequenciesthe frequencies at which to refresh information are defined;
Original Bare Metal Cyber perspective

From control text to operational evidence

Use Information Refresh as a testable risk decision. Translate the official statement into accountable people, repeatable processes, configured technology, and evidence that demonstrates the outcome over time. In this family, pay particular attention to flaw remediation, malicious-code protection, monitoring, integrity, and trustworthy information handling.

Implementation workflow

  • Define the control boundary, responsible owner, inherited portions, and systems or processes in scope.
  • Resolve each organization-defined parameter before declaring the control implemented.
  • Document how the implementation satisfies every clause of the official control statement.
  • Collect evidence as a normal byproduct of operation rather than only before an assessment.
  • Review exceptions, changes, and monitoring results on a risk-based cadence.

Evidence examples

  • patch and remediation records
  • malware protection configuration
  • monitoring alerts and response records
  • integrity validation and exception reports

Common failure patterns

  • patch compliance hides unsupported assets
  • alerts generated without response ownership
  • exceptions never expire
  • integrity monitoring excludes critical configurations

Questions practitioners should ask

  • What risk decision is this control intended to support in this system?
  • Which parts are implemented locally, inherited, shared, or not applicable—and what evidence supports that decision?
  • Do the documented narrative, deployed configuration, operating process, and collected evidence agree?
  • What event or threshold requires the implementation to be reviewed or changed?
Official NIST SP 800-53A content

Assessment objectives and methods

Show the assessment objective

the [Organization-defined: information] is refreshed [Organization-defined: frequencies] or is generated on demand and deleted when no longer needed.

Examine

  • System and information integrity policy
  • system and information integrity procedures
  • personally identifiable information processing policy
  • procedures addressing software and information integrity
  • system design documentation
  • system configuration settings and associated documentation
  • information refresh procedures
  • list of information to be refreshed
  • system security plan
  • privacy plan
  • other relevant documents or records

Interview

  • Organizational personnel responsible for refreshing information
  • organizational personnel with information security and privacy responsibilities
  • organizational personnel with systems security engineering responsibilities
  • system developers

Test

  • Mechanisms for information refresh
  • organizational processes for information refresh
Official relationships

Related controls

These relationships come from the official OSCAL catalog. They indicate useful dependencies or context, not automatic inheritance or equivalence.

Source record

Authoritative sources